Image forming apparatus, image forming method, and computer-readable recording medium having image forming program recorded therein

ABSTRACT

There is provided an image forming apparatus including: an image data acquiring unit that acquires image data of an image formed on a sheet; an identification information acquiring unit that acquires identification information that identifies the sheet on which the image is formed; an image forming unit that forms an image based on the image data acquired by the image data acquiring unit on the sheet with a decolorable colorant which becomes colorless by a predetermined chemical reaction and that forms an identification information image based on the identification information on the sheet with a non-decolorable colorant which does not become colorless by the chemical reaction by which the decolorable colorant becomes colorless; and a storage control unit that stores the identification information and the image data of the image to be formed on the sheet, on which the identification information image corresponding to the identification information is formed, in a predetermined storage region in a correlated manner.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from:U.S. provisional application 61/173,104, filed on Apr. 27, 2009; U.S.provisional application 61/173,106, filed on Apr. 27, 2009; and U.S.provisional application 61/242,996, filed on Sep. 16, 2009; the entirecontents of each of which are incorporated herein by reference.

TECHNICAL FIELD

The description relates to a technique of reproducing images when animage forming apparatus forms an image using a decolorable colorantwhich is made colorless with thermal energy or the like, and the imageis decolored, and accordingly, the image disappears.

BACKGROUND

Conventionally, a decolorable colorant capable of erasing colors, suchas ink containing a leuco dye was used to print images on a paper inorder to reuse papers on which images were printed by an image formingapparatus such as MFP (Multi-Function Peripheral). The paper printedwith the decolorable colorant can be reused for printing since achemical reaction occurs therein when heat or the like is appliedthereto, thus decoloring the decolorable colorant.

However, when printing is performed using a colorant which is madecolorless with heat or the like in order to make a paper reusable, it isdifficult to maintain images for a longer period of time compared to aprinting method that uses a general non-decolorable toner and ink andthe like. For example, when a paper printed with a colorant which ismade colorless with heat is left in a place such as an inside of avehicle that is heated in the summer season, the image on the paper willbe decolored, and accordingly, the information printed on the paper willdisappear. In addition, when a user carelessly performs processes thaterase images printed with a decolorable colorant with the aim to recyclea paper, the printed information will disappear.

Moreover, another problem is the difficulty to discriminate at a glancebetween an image printed with a decolorable colorant and an imageprinted with a general non-decolorable colorant. Therefore, when a usertried to reuse a printed paper, it was difficult to determine whetherthe printed paper could be reused when the images on the paper aredecolored.

SUMMARY

The description relates to an image forming apparatus including: animage data acquiring unit that acquires image data of an image formed ona sheet; an identification information acquiring unit that acquiresidentification information that identifies the sheet on which the imageis formed; an image forming unit that forms an image based on the imagedata acquired by the image data acquiring unit on the sheet with adecolorable colorant which becomes colorless by a predetermined chemicalreaction and that forms an identification information image based on theidentification information on the sheet with a non-decolorable colorantwhich does not become colorless by the chemical reaction by which thedecolorable colorant becomes colorless; and a storage control unit thatstores the identification information and the image data of the image tobe formed on the sheet, on which the identification information imagecorresponding to the identification information is formed, in apredetermined storage region in a correlated manner.

The description also relates to an image forming method including:acquiring image data of an image formed on a sheet; acquiringidentification information that identifies the sheet on which the imageis formed; forming an image based on the acquired image data on thesheet with a decolorable colorant which becomes colorless by apredetermined chemical reaction and forming an identificationinformation image based on the identification information on the sheetwith a non-decolorable colorant which does not become colorless by thechemical reaction by which the decolorable colorant becomes colorless;and storing the identification information and the image data of theimage formed on the sheet, on which the identification information imagecorresponding to the identification information is formed, in apredetermined storage region in a correlated manner.

The description further relates to a computer-readable recording mediumhaving an image forming program recorded therein, the program causing acomputer to execute processing including: acquiring image data of animage formed on a sheet; acquiring identification information thatidentifies the sheet on which the image is formed; forming an imagebased on the acquired image data on the sheet with a decolorablecolorant which becomes colorless by a predetermined chemical reactionand forming an identification information image based on theidentification information on the sheet with a non-decolorable colorantwhich does not become colorless by the chemical reaction by which thedecolorable colorant becomes colorless; and storing the identificationinformation and the image data of the image formed on the sheet, onwhich the identification information image corresponding to theidentification information is formed, in a predetermined storage regionin a correlated manner.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the configuration of an MFP serving as animage forming apparatus according to a first embodiment and theconfiguration of a system including the MFP.

FIG. 2 is a diagram showing the configuration of the MFP according tothe first embodiment.

FIG. 3 is a functional block diagram showing functional blocks of theMFP.

FIG. 4 is a diagram showing a data structure of an image data DB storedin an HDD.

FIG. 5 is a functional block diagram showing image forming functionalblocks in the reproduction mode of the MFP.

FIG. 6 is a flowchart showing the flow of an image forming process inthe rewritable print mode of the MFP.

FIG. 7 is a flowchart showing the flow of an image forming process inthe reproduction mode of the MFP.

FIG. 8 is a configuration diagram showing a modification of the MFPaccording to the first embodiment.

FIG. 9 is a configuration diagram showing another modification of theMFP according to the first embodiment.

FIG. 10 is a diagram showing the configuration of an MFP according to asecond embodiment.

FIG. 11 is a configuration diagram showing a modification of the MFPaccording to the second embodiment.

FIG. 12 is a diagram showing the configuration of an MFP according to athird embodiment.

FIG. 13 is a functional block diagram showing functional blocks in thereproduction mode of an MFP according to a fourth embodiment.

FIG. 14 is a flowchart showing the flow of an image forming process inthe reproduction mode of the MFP according to the fourth embodiment.

FIG. 15 is a diagram showing the configuration of an MFP according to afifth embodiment and the configuration of a system including a server inwhich an image data DB is stored.

FIG. 16 is an enlarged view of the vicinity of a sheet supply unit of anMFP according to a sixth embodiment.

FIG. 17 is a functional block diagram of the MFP according to the sixthembodiment.

FIG. 18 is a flowchart showing the flow of a sheet sorting process bythe MFP according to the sixth embodiment.

FIG. 19 is a diagram showing the configuration of an MFP according to aseventh embodiment.

FIG. 20 is a diagram showing the relationship between a fixingtemperature range and a decoloring temperature range.

FIG. 21 is a diagram showing the relationship between a fixingtemperature range and a decoloring temperature range.

FIG. 22 is a diagram showing the relationship between a fixingtemperature range and a decoloring temperature range.

DETAILED DESCRIPTION

Hereinafter, embodiments will be described with reference to thedrawings.

First Embodiment

FIG. 1 is a diagram showing the configuration of an MFP (Multi-FunctionPeripheral) 1 serving as an image forming apparatus according to thepresent embodiment and the configuration of a system including the MFP1. FIG. 2 is a diagram showing the configuration of the MFP 1 accordingto the present embodiment. The system of the present embodiment has aconfiguration in which the MFP 1 and other devices such as a clientterminal 160 are connected via a network 150. Each device constitutingthe system will be described in detail below.

The MFP 1 of the present embodiment is an MFP capable of performing twokinds of image forming processes: one image forming process uses adecolorable colorant which becomes colorless by a chemical reaction whenit is heated to a predetermined temperature, and the other image formingprocess uses a non-decolorable colorant which maintains its color evenafter it is heated to the predetermined temperature. In the following, amode wherein images are formed with a decolorable colorant will bereferred to as a “rewritable print mode” (however, the image formingprocess using the decolorable colorant is not limited to the case ofaiming at the reuse of the sheet).

The MFP 1 of the present embodiment performs processes of forming imageswith a decolorable colorant to enable the reuse of a sheet, forming anidentification information image corresponding to identificationinformation for identifying the sheet with a non-decolorable colorant,and storing the identification information and image data formed by thedecolorable colorant in a predetermined storage region in a correlatedmanner. By doing so, even when the image formed with the decolorablecolorant is carelessly decolored, and accordingly, information formed onthe sheet disappears, the MFP 1 of the present embodiment is able toreproduce the decolored images to reappear on the sheet by using theidentification information image corresponding to the identificationinformation formed on the sheet. In the following, a mode whereindecolored images are formed on the sheet again by using theidentification information will be referred to as a “reproduction mode.”

Hereinafter, components realizing these functions of the MFP 1 accordingto the present embodiment will be described.

The MFP 1 includes a processor 2, a memory 4, an HDD (Hard Disc Drive)6, a first image forming unit 8 that forms images using anon-decolorable colorant, a second image forming unit 10 that formsimages using a decolorable colorant, an image reading unit 12, a displaypanel 14, an operation input unit 16, a sheet supply unit 18, a FAX unit20, a finisher device 22, an image reading sensor 24, and the like.

The processor 2 executes various processes of the MFP 1 such as, forexample, an image forming process and an image reading process, based ona print job, an operation input, and the like sent from the clientterminal 160 or the like. When images are formed in the rewritable printmode, namely images are formed using a decolorable colorant in order toenable the reuse of a sheet, the processor 2 of the present embodimentcontrols a process of causing the first image forming unit 8 to form anidentification information image on a sheet using a non-decolorablecolorant and causing the second image forming unit 10 to form an imagewith image data acquired as an image forming job on the sheet using adecolorable colorant. In addition, the processor 2 executes a process ofstoring the image data formed with the decolorable colorant and theidentification information on the sheet in the HDD 6 in a correlatedmanner. In addition, as the image forming process in the reproductionmode, the processor 2 executes a process of acquiring disappeared imagedata from the identification information image that is formed on thesheet and forming an image with the image data on the sheet based on aninstruction from the operation input unit 16 or the like to reproducedecolored images. The processor 2 executes processing for realizingthese various functions by executing a program stored in the memory 4.Details of the function executing the above-described processes will bedescribed with reference to the functional block diagram of FIG. 3.Moreover, as the processor 2, a CPU (Central Processing Unit), an MPU(Micro Processing Unit) capable of executing the same arithmeticalprocessing as the CPU, and the like can be used. Furthermore, a part orthe entirety of the functions of the MFP 1 may be implemented as an ASIC(Application Specific Integrated Circuit) serving as a processor.

The memory 4 stores programs for executing the image forming process andthe above-described processes of the MFP 1 according to the presentembodiment. Moreover, the memory 4 is used for temporarily storing imagedata generated by RIP processing during the image forming process and aswork areas of various applications. In addition, the memory 4 has afunction of temporarily storing signals such as an image forming jobacquired via the network 150, operation input signals from the operationinput unit 16, and the like. The memory 4 can be configured, forexample, by a RAM (Random Access Memory), a ROM (Read Only Memory), aDRAM (Dynamic Random Access Memory), an SRAM (Static Random AccessMemory), a VRAM (Video RAM), a flash memory, and the like.

The HDD 6 is an auxiliary storage device for storing various kinds ofinformation of the MFP 1. In addition, the HDD 6 of the presentembodiment stores an image data database (DB) 100 in which theidentification information for identifying a sheet on which an image isformed with a decolorable colorant and the formed image data are storedin a correlated manner. Although in the present embodiment, an HDD isexemplified as an example of the auxiliary storage device of the MFP 1,the auxiliary storage device is not limited to this, but for example, aflash memory, an SSD (Solid-State Device), a magnetic disk other thanthe HDD, and the like may be used.

The first image forming unit 8 is a device that forms images by ageneral electrophotographic method. The first image forming unit 8 ofthe present embodiment forms an identification information imagecorresponding to sheet identification information when images are formedin the rewritable print mode. As shown in FIG. 2, the first imageforming unit 8 includes photoconductive drums 8K, 8C, 8M, and 8Y, anintermediate transfer belt 8B, a fixing device 8F, and the like.

The photoconductive drums 8K to 8Y form electrostatic latent imagescorresponding to color data of each of the colors black (K), cyan (C),magenta (M), and yellow (Y) constituting the image data to be formed onthe photoconductive surface of each of the photoconductive drums 8K to8Y, and the electrostatic latent images are made visible as developerimages by a developer (toner) supplied from a developing roller notshown. The developer images formed on the photoconductive drums 8K to 8Yare transferred (so-called primarily transferred) to the intermediatetransfer belt 8B.

The intermediate transfer belt 8B transfers (so-called secondarilytransfers) the transferred developer images to a sheet serving as animage forming target at a transfer position T shown in FIG. 2.

The fixing device BF thermally fixes the developer images transferred tothe sheet at the transfer position T to the sheet.

Here, “identification information” is information for identifying asheet on which an image is formed, and in the present embodiment, isinformation for identifying a sheet on which an image is formed in therewritable print mode in order to correlate the image data based onwhich an image is formed in the rewritable print mode to a sheet onwhich an image is formed based on the image data. Moreover,“identification information image” is an image that is formed on a sheetcorresponding to the identification information. For example, theidentification information is a character string made up of numbers,characters, and the like, and the identification information image is animage that can be read by an image reading sensor, such as a barcode ora QR code (registered trademark) representing the identificationinformation. Identification information itself of a character string maybe used as the identification information image as long as theidentification information of the character string can be read. In theimage data DB 100 described later, the identification information andthe image data based on which an image is formed with a decolorablecolorant are stored in a correlated manner, so that it is possible toidentify image data based on which an image is formed on the sheet fromthe identification information identified by reading an identificationinformation image corresponding to the identification information.

The second image forming unit 10 is a device that forms images by an inkjet method using a decoloring ink which is a decolorable colorant. Inthe present embodiment, the second image forming unit 10 forms an imageof image data acquired as an image forming job when images are formed inthe rewritable print mode. The second image forming unit 10 includesprint heads 10K, 10C, 10M, and 10Y which correspond to the decoloringinks of each of the colors black (K), cyan (C), magenta (M), and yellow(Y), and corresponding inks are discharged from the print heads so thatdecoloring ink images are formed on a sheet.

Here, the decoloring ink which is a decolorable colorant may be a dyesuch as a leuco dye. The decoloring ink becomes colorless when it isheated to a temperature of about 80 to 100° C.

The image reading unit 12 is a general image reading device which isprovided to a copying machine, an image scanner, and the like. The imagereading unit 12 is used when a user copies or scans an original documentusing the MFP 1.

The display panel 14 displays various kinds of information such assetting information, operation status, and the like of the MFP 1. Thedisplay panel 14 can be configured, for example, by an electronic paper,an LCD (Liquid Crystal Display), an EL (Electronic Luminescence), a PDP(Plasma Display Panel), a CRT (Cathode Ray Tube), and the like.Moreover, when the display panel 14 is configured by a touch paneldisplay, the display panel 14 can implement a part or the entirety ofthe functions of the operation input unit 16.

The operation input unit 16 is used for designating copying and scanningconditions and inputting FAX Numbers. The operation input unit 16 can beconfigured, for example, by input keys for numbers or the like, akeyboard, a mouse, a touch panel, a touchpad, a graphics tablet, anddedicated buttons.

The sheet supply unit 18 stores sheets such as papers on which an imageis formed and supplies the stored sheet to the image forming unit whenforming images. The sheet supply unit 18 of the present embodimentincludes a sheet supply unit 18 a in which unused sheets on which animage is not formed yet at all are stored, a reused sheet supply unit 18b in which reused sheets are stored which have been subjected to adecoloring process for reuse so that images disappear, and a manualsupply unit 18 m. Since the reused sheets stored in the reused sheetsupply unit 18 b are sheets on which images had been formed with adecolorable colorant, identification information is attached to thesheets, and an identification information image corresponding to theidentification information is formed at a predetermined position of eachof the sheets. Moreover, in the MFP 1 of the present embodiment, whenimages are formed in the reproduction mode, sheets having decoloredimages are stored in the manual supply unit 18 m and supplied from themanual supply unit 18 m to the image forming unit.

The FAX unit 20 is an apparatus that sends and receives facsimilesignals in the MFP 1.

The finisher device 22 is a device for sorting sheets into each copywhen printing multiple copies. Moreover, the finisher device 22 is alsocapable of performing the role of a discharge unit that storesdischarged sheets.

The image reading sensor 24 reads the identification information imageprinted at a predetermined position of a reused sheet when the reusedsheet is supplied from the reused sheet supply unit 18 b and images areformed thereon. Moreover, when in the reproduction mode, a decoloredimage is formed on a sheet again on which the image had been formed, theimage reading sensor 24 reads the identification information image thatwas formed on the sheet with a non-decolorable colorant. Identificationinformation is acquired from the identification information image readby the image reading sensor 24, and image data correlated to theacquired identification information are identified from the image dataDB 100, whereby the image can be reproduced by forming the image data onthe sheet again.

The configuration of the MFP 1 was described hereinabove.

Next, other system configurations shown in FIG. 1 other than the MFP 1will be described. The network 150 is a communication network that isconfigured, for example, by the Internet, a LAN (Local Area Network),and a WAN (Wide Area Network).

The client terminal 160 connected to the network 150 outputs an imageforming job such as a PDL file to the MFP 1 via the network 150. Theclient terminal 160 is a terminal device such as a computer. The clientterminal 160 includes a processor 160 a, a memory 160 b, and the like,and is capable of realizing various functions by executing programsstored in the memory 160 b or the like.

Next, the image forming function of the MFP 1 according to the presentembodiment will be described.

First, among the image forming processes of the MFP 1 according to thepresent embodiment, an image forming process based on an image formingjob will be described. FIG. 3 is a functional block diagram showingfunctional blocks of the MFP 1. The functional blocks below areimplemented when the processor 2 reads and executes image formingprograms stored in the memory 4 and the HDD 6.

The MFP 1 of the present embodiment includes a print job acquiring unit102, an RIP unit 104, a setting information determining unit 106, asheet supply control unit 108, an image reading sensor control unit 110,a first image forming unit control unit 112, a second image forming unitcontrol unit 114, and an image data storage control unit 116.

The print job acquiring unit 102 acquires an image forming job thatinstructs to form images and that is sent from the client terminal 160or the like via the network 150. The print job may contain the followinginformation: a PDL (Page Description Language) file based on which animage is formed, setting information designating whether or not imageformation will be performed in the rewritable print mode, settinginformation as to from which supply unit of the sheet supply unit 18 asheet will be supplied, and the like.

The RIP unit 104 is an RIP (Raster Image Processor) that executes aprocess of interpreting a PDL file constituting the print job andconverting the PDL file into raster image data. When the rewritableprint mode is set, the RIP unit 104 outputs the raster image data to thesecond image forming unit control unit 110 in order to form images witha decolorable colorant. On the other hand, when the rewritable printmode is not set, and images are formed with a general non-decolorablecolorant, the RIP unit 104 outputs the raster image data to the firstimage forming unit control unit 112 (see the dotted line in FIG. 3).

The setting information determining unit 106 determines whether or notit is set such that images will be formed in the rewritable print modewhen the MFP 1 acquires a print job. Specifically, when informationdesignating that images will be formed in the rewritable print mode isincluded in the print job, the setting information determining unit 106determines that images will be formed in the rewritable print mode andcauses the RIP unit 104 to output raster image data to the second imageforming unit control unit 110. Moreover, when it is preset by anoperation input on the operation input unit 16 or the like such thatimages will be formed in the rewritable print mode, the settinginformation determining unit 106 may similarly determine that imageswill be formed in the rewritable print mode and cause the raster imagedata to be output to the second image forming unit control unit 110.Furthermore, the setting information determining unit 106 determineswhether it is set such that a sheet will be supplied from either thesheet supply unit 18 a or the reused sheet supply unit 18 b.

The setting information determining unit 106 determines based on thesetting information as to the rewritable print mode and the settinginformation as to the sheet supply unit 18 whether a new identificationinformation image will be formed on a sheet or an identificationinformation image which was already formed on the sheet will be read.That is to say, if the rewritable print mode is set, and the sheetsupply unit 18 a storing unused sheets is set as the sheet supply unit,since the identification information image is not formed on the sheetson which an image will be formed later, the setting informationdetermining unit 106 outputs an instruction to the first image formingunit control unit 112 to form an identification information imagecorresponding to new identification information. On the other hand, ifthe reused sheet supply unit 18 b is designated, the setting informationdetermining unit 106 outputs an instruction to the image reading sensorcontrol unit 110 to cause the image reading sensor 24 to a process ofreading an identification information image of a sheet that istransported for image formation.

The sheet supply control unit 108 executes a process of supplying asheet from a designated sheet supply unit based on the above-describedsetting information as to the sheet supply unit 18 included in the printjob.

As described above, the image reading sensor control unit 110 causes theimage reading sensor 24 to execute a process of reading anidentification information image formed on a reused sheet that istransported for image formation based on the determination results ofthe setting information determining unit 106.

When the setting information as to the sheet supply unit 18 is set suchthat sheets will be supplied from the sheet supply unit 18 a, the firstimage forming unit control unit 112 executes a process of causing thefirst image forming unit 8 to form an identification information imagecorresponding to new identification information assigned to a sheet onwhich an image is to be formed with a non-decolorable colorant. In thiscase, the first image forming unit control unit 112 generates newidentification information so as to be different from the identificationinformation that was already stored by referencing the image data DB 100stored in the HDD 6 (this generating operation corresponds to thefunction of an identification information acquiring unit), generates anidentification information image corresponding to the identificationinformation, forms the identification information image on a sheet, andcauses the first image forming unit 8 to perform image formation. Inthis case, the first image forming unit control unit 112 controls suchthat the identification information image is formed in a predeterminedregion (for example, a header region or a footer region of a sheet)different from an image region of a sheet in which images are formed bythe second image forming unit 10.

Specifically, if serial numbers starting from “1000” are attached asidentification information, and identification information up to “1010”was registered when the first image forming unit control unit 112referenced the image data DB 100, the first image forming unit controlunit 112 will generate “1011” as the identification information andgenerate an identification information image such as a barcodecorresponding to “1011.”

When the rewritable print mode is designated, the second image formingunit control unit 114 executes a process of causing the second imageforming unit 10 to form the raster image data generated by the RIP unit104 with a decoloring ink which is a decolorable colorant.

The image data storage control unit 116 stores the image data based onwhich an image is formed by the second image forming unit 10 in theimage data DB 100 to be correlated to new identification informationgenerated by the first image forming unit control unit 112 oridentification information that was registered in the image data DB 100and that corresponds to the identification information image read by theimage reading sensor 24.

Next, a data structure of the image data DB 100 will be described. FIG.4 is a diagram showing the data structure of the image data DB 100stored in the HDD 6. In the image data DB 100, for example, as shown inFIG. 4, identification information, corresponding image data, the dateand time when an image is formed on a sheet based on the image data, andthe like are stored in a correlated manner. If images were formed pluraltimes on the same sheet in the rewritable print mode, these past pluralimages may be stored in the image data DB 100. For example, the sheethaving identification information of 1002 in FIG. 4 was formed with thefirst image data (10021.jpeg) on Mar. 10, 2009, and was recycled laterfor forming images up to four times. When images were formed pluraltimes on the same sheet, it is not always necessary to store all of thepast image data, but a storage period, the number of data items, or thelike may be changed as necessary.

When an image is formed based on the image data acquired as the imageforming job with a decolorable colorant by the above-described functionsof the MFP 1, it is possible to form an identification information imagecorresponding to sheet identification information identifying a sheet ona sheet on which an image is formed with a non-decolorable colorant.Therefore, it is possible to store the identification informationcorresponding to the identification information image and the image databased on which an image is formed with the decolorable colorant in acorrelated manner.

Next, among the image forming processes of the MFP 1 according to thepresent embodiment, the image forming process in the reproduction modewill be described. FIG. 5 is a function block diagram showing functionalblocks in the reproduction mode of the MFP 1. Similarly, the functionalblocks below are implemented when the processor 2 reads and executesimage forming programs stored in the memory 4 and the HDD 6.

The MFP 1 of the present embodiment includes an image reproduction jobacquiring unit 502, the sheet supply control unit 108, the image readingsensor control unit 110, an image data acquiring unit 504 serving as astored image data acquiring unit, and the second image forming unitcontrol unit 114.

The image reproduction job acquiring unit 502 acquires, from theoperation input unit 16 or the like, a print job in the reproductionmode that instructs the execution of a process of reproducing an imagethat was decolored and disappeared.

The sheet supply control unit 108 executes a process of supplying sheetsfrom the manual supply unit 18 m when the image reproduction jobacquiring unit 502 acquires the print job in the reproduction mode. Thisis to form again the disappeared image on the original sheet from whichthe image disappeared.

The image reading sensor control unit 110 executes a process of causingthe image reading sensor 24 to read an identification information imageformed on the sheet supplied from the manual supply unit 18 m.

The image data acquiring unit 504 references the image data DB 100stored in the HDD 6 based on the identification information read by theimage reading sensor 24 under the control of the image reading sensorcontrol unit 110 to acquire the nearest image data that correspond tothe decolored image and that are correlated to the identificationinformation. If plural image data are stored for each of theidentification information in the image data DB 100, any past image datamay be reproduced in addition to the latest image. This can be realized,for example, by displaying a list of image data corresponding to theacquired identification information on the display panel 14 and allowinga user to select data to be reproduced through an operation on theoperation input unit 16.

The second image forming unit control unit 114 executes a process ofcausing the second image forming unit 10 to form the image data acquiredby the image data acquiring unit 504 on a sheet.

By the above-described functions of the MFP 1 according to the presentembodiment, even when a colorant on a sheet is decolored, andaccordingly, an image disappears, it is possible to reproduce thedecolored image on the sheet again using the identification informationimage formed with the non-decolorable colorant.

Although the above-described functional blocks were described to beimplemented when the processor 2 reads the image processing programsstored in the memory 4 or the like, the invention is not limited tothis, but a part of the functional blocks may be implemented by aprocessing circuit such as an ASIC (Application Specific IntegratedCircuit) or may be implemented by a processing circuit such as an ASIChaving the entirety of the functional blocks.

Next, the flow of the image forming process in the rewritable print modeby the MFP 1 will be described. FIG. 6 is a flowchart showing the flowof the image forming process in the rewritable print mode of the MFP 1.

First, in Act 101, the print job acquiring unit 102 acquires a print jobvia the network 150.

Subsequently, in Act 102, the RIP unit 104 rasterizes a PDL fileincluded in the acquired print job.

Subsequently, in Act 103, the setting information determining unit 106determines whether or not the rewritable print mode is set based on thesetting information included in the print job. When it is determinedthat the rewritable print mode is set (Act 103: Yes), the settinginformation determining unit 106 determines in Act 104 whether or not itis set in the setting information included in the print job or by anoperation input on the operation input unit 16 such that sheets will besupplied from the reused sheet supply unit 18 b.

When it is determined that it is set such that a reused sheet will besupplied from the reused sheet supply unit 18 b (Act 104: Yes), theimage reading sensor control unit 110 executes, in Act 105, a process ofcausing the image reading sensor 24 to read an identificationinformation image formed on a sheet supplied from the reused sheetsupply unit 18 b.

Subsequently, in Act 106, the second image forming unit control unit 114causes the second image forming unit 10 to perform image formation basedon raster image data generated by the RIP unit 104.

Subsequently, in Act 107, the image data storage control unit 116 storesthe image data based on which an image is formed by the second imageforming unit 10 and the identification information identified by theimage reading sensor 24 reading the identification information image inthe image data DB 100 in a correlated manner.

On the other hand, when the setting information determining unit 106determines in Act 104 that it is set such that unused sheets will besupplied from the sheet supply unit 18 a (Act 104: No), the first imageforming unit control unit 112 generates, in Act 108, new identificationinformation that was not registered by referencing the image data DB 100of the HDD 6 in order to form a new identification information image ona sheet.

Subsequently, in Act 109, the first image forming unit control unit 112causes the first image forming unit 8 to form an identificationinformation image corresponding to the generated identificationinformation on a sheet, and the second image forming unit control unit114 causes the second image forming unit 10 to form an image on thesheet using the raster image data generated by the RIP unit 104.

Subsequently, in Act 110, the image data storage control unit 116 storesthe image data based on which an image is formed by the second imageforming unit 10 and the newly generated identification information inthe image data DB 100 in a correlated manner.

The flow of the process of forming images in the rewritable print modeby the MFP 1 according to the present embodiment is describedhereinabove. By the image forming processes of Acts 105 to 107, imagesare formed on a reused sheet with a decolorable colorant, whereas by theimage forming processes of Acts 108 to 110, images generated by the RIPprocessing are formed on an unused sheet with a decolorable colorant andan identification information image is formed thereon with anon-decolorable colorant.

Moreover, when the setting information determining unit 106 determinesin Act 103 that the rewritable print mode is not set in the print job(Act 103: No), the MFP 1 executes a normal image forming process using anon-decolorable colorant in Act 111.

Next, the flow of the process of forming images in the reproduction modein order to reproduce a decolored image when an image on a sheet formedin the rewritable print mode in the described manner is decolored willbe described. FIG. 7 is a flowchart showing the flow of the imageforming process in the reproduction mode of the MFP 1.

First, a user places a sheet having a decolored image on the manualsupply unit 18 m and operates the operation input unit 16 to issue aninstruction to execute an image forming process in the reproductionmode. Then, in Act 201, the image reproduction job acquiring unit 502acquires an image reproduction job from the operation input unit 16.

Subsequently, when the image reproduction job is acquired in Act 201,the sheet supply control unit 108 causes, in Act 202, the sheet supplyunit 18 to execute a process of supplying a sheet which is a targetmaterial for reproducing an image and which is placed on the manualsupply unit 18 m to the image forming unit.

Subsequently, in Act 203, the image reading sensor control unit 110causes the image reading sensor 24 to execute a process of reading anidentification information image formed in a predetermined region of asheet being transported.

Subsequently, in Act 204, the image data acquiring unit 504 referencesthe image data DB 100 based on the identification information identifiedfrom the identification information image read by the image readingsensor 24 to acquire image data that are the latest among the registeredimage data correlated to the identification information. For example, inthe case of the image data DB 100 shown in FIG. 4, if the identificationinformation is 1002, the reproduced image data will be “10024.jpeg”which is the latest data.

Subsequently, in Act 205, the second image forming unit control unit 114executes a process of causing the second image forming unit 10 to forman image based on the image data acquired in Act 204 on a sheet.

By the above-described processes, it is possible to reproduce an imagethat was decolored and disappeared on a sheet having the decolored imageusing the identification information image formed with a non-decolorablecolorant that remains colorful without being decolored.

As described above, according to the MFP 1 of the present embodiment, itis possible to form an image on a sheet with a decolorable colorant andform an identification information image on the sheet with anon-decolorable colorant. In addition, according to the MFP 1 of thepresent embodiment, it is possible to store image data based on which animage is formed with the decolorable colorant and sheet identificationinformation in a correlated manner. In this way, even when an imageformed with a decolorable colorant is carelessly decolored, it ispossible to read the identification information image formed with thenon-decolorable colorant to reproduce corresponding image data on thesheet. Therefore, it is possible to ensure good maintenance of databased on which an image is formed while enabling the reuse of a sheet.

Although the present embodiment was described such that image formationis performed in the rewritable print mode when an image forming job isdesignated to be performed in the rewritable print mode, image formationmay be performed in the rewritable print mode similarly when an image isformed based on a received FAX document or copying a document. In thiscase, a user may input settings so that an image of a FAX document and acopied document will be formed in the rewritable print mode through anoperation input on the operation input unit 16 or the like.

Moreover, although the present embodiment was described such that thedecolored image is formed on a sheet (paper) again, the invention is notlimited to this. If it is only necessary to view the decolored image, aprocess of identifying the decolored image by reading the identificationinformation image of the sheet having the decolored image and displayingthe decolored image on the display panel 14 of the MFP 1 or otherdisplay devices such as a display of the client terminal 160 on thenetwork 150 may be performed.

Furthermore, although the present embodiment was described such that thedecolored image is formed on the same sheet again on which the image wasoriginally formed with a decolorable colorant, the invention is notlimited to this, but the decolored image may be identified and formed ona different sheet. Moreover, when the decolored image is formed on thesheet having the decolored image or a different sheet, it is not alwaysnecessary to form the decolored image with a decolorable colorant butthe decolored image may be formed with a non-decolorable colorant.

Furthermore, although the present embodiment was described such that thedecolorable colorant is decolored with heat, the invention is notlimited to this, the decolorable colorant may be a colorant that isdecolored with light energy and may be a colorant that is decolored byreacting with other materials.

Furthermore, although the present embodiment was described such that theMFP 1 has an entirety of the image forming function in the rewritableprint mode and an entirety of the image forming function in thereproduction mode, the invention is not limited to this, but an externaldevice such as the terminal 160 may have a part of the function. In thiscase, a program corresponding to the function realized in the terminal160 may be stored in the memory 160 b or the like so that the functionof the terminal 160 is realized when the processor 160 a executes theprogram.

Furthermore, although the present embodiment was described such that theidentification information image corresponding to the identificationinformation identifying a sheet is formed on the sheet, the invention isnot limited to this, but an identification information image correlatedto an image formed with a decolorable colorant may be formed on thesheet. That is, an MFP serving as an image forming apparatus may beconfigured to include an image data acquiring unit that acquires imagedata of an image formed on a sheet, an identification informationacquiring unit that acquires identification information that identifiesthe image formed on the sheet, and an image forming unit that forms animage based on the image data acquired by the image data acquiring uniton the sheet with a decolorable colorant which becomes colorless by apredetermined chemical reaction and that forms an identificationinformation image based on the identification information that isacquired by the identification information acquiring unit and thatcorresponds to the image on the sheet with a non-decolorable colorantwhich does not become colorless by the chemical reaction that makes thedecolorable colorant colorless. According to such a configuration, theimage data of the image formed with the decolorable colorant are storedin the image data DB 100 to be correlated to the identificationinformation. When the image formed with the decolorable colorant isdecolored, and it is desired to reproduce that image on the sheet, theimage reading sensor 24 or the like reads the identification informationimage formed on the sheet, and the image data acquiring unit 504references the image data DB 100 to acquire the image data correlated tothe read identification information. Therefore, by forming an image onthe sheet based on the acquired image data, it is possible to reproducethe decolored image on the sheet. As described above, by storing theidentification information to be correlated to the image data, it ispossible to reproduce the decolored image.

Furthermore, although the present embodiment was described such thatsheets are supplied from the manual supply unit 18 m during imageformation in the reproduction mode, the invention is not limited tothis, but for example, as shown in FIG. 8, a dedicated manual supplyunit 18 m′ for use during image formation in the reproduction mode maybe provided to the MFP 1 so that sheets are supplied from the dedicatedmanual supply unit 18 m′.

In addition, as another modification, as shown in FIG. 9, an MFP 1′ maybe configured to include a decoloring device 26 that is disposed to beclose to the reused sheet supply unit 18 b so as to decolor an image ona sheet formed with a decolorable colorant, an image reading sensor 24′that is disposed between the decoloring device 26 and the reused sheetsupply unit 18 b so as to read an identification information image, andan image formed sheet supply unit 28 that is disposed below the finisherdevice 22 so as to store sheets on which images are formed with adecolorable colorant, and that has a function of sequentially supplyingthe sheets to the decoloring device 26.

The decoloring device 26 is a device that decolors images formed on asheet with a decolorable colorant by heating the sheet to a temperatureequal to or higher than a temperature at which the decolorable colorantbecomes colorless.

According to such a configuration, when image formation is performed inthe rewritable print mode, a sheet is supplied from the image formedsheet supply unit 28 to the decoloring device 26 and is subjected to adecoloring process. The sheet is then stored in the reused sheet supplyunit 18 b as a reused sheet having a decolored image and is used forimage formation in the rewritable print mode. An image forming processin the rewritable print mode is the same as that described in the firstembodiment. On the other hand, when image formation is performed in thereproduction mode, the image reading sensor 24′ reads an identificationinformation image formed on a sheet, which was subjected to thedecoloring process by the decoloring device 26, with a non-decolorablecolorant, and the sheet is transported to the second image forming unit10 via the sheet supply unit 18 b′ for the reproduction mode. Then, theabove-described image data acquiring unit 504 acquires the image datacorresponding to the identification information read by the imagereading sensor 24′ from the image data DB 100, and an image is formedbased on the image data by the second image forming unit 10. In themodification of the first embodiment, it is possible to reproducereliably an image that was decolored.

Second Embodiment

Next, a second embodiment will be described. An MFP 1 a of the presentembodiment is configured to perform both image formation with anon-decolorable colorant and image formation with a decolorable colorantby an ink jet method. FIG. 10 is a diagram showing the configuration ofthe MFP 1 a according to the present embodiment. The MFP 1 a of thepresent embodiment includes a first image forming unit 80 of an ink jetmethod instead of the first image forming unit 8 of the firstembodiment. The second image forming unit 10 is an image forming unit ofan ink jet method similar to the first embodiment. In the following, theMFP 1 a of the present embodiment will be described, and the sameconfiguration as the first embodiment will be denoted by the samereference numerals and description thereof will be omitted.

The first image forming unit 80 of the present embodiment includes printheads 80K, 80C, 80M, and 80Y that discharge a non-decoloring ink whichis a non-decolorable colorant, the intermediate transfer belt 8B, andthe like. The print heads 80K, 80C, 80M, and 80Y are configured todischarge ink of the colors black, cyan, magenta, and yellow,respectively. The print heads 80K to 80Y discharge a non-decoloring inkto the intermediate transfer belt 8B, and a non-decoloring ink image isformed on the intermediate transfer belt 8B. The non-decoloring inkimage formed on the intermediate transfer belt 8B is transferred to asheet at a transfer position T.

In the present embodiment, the first image forming unit 80 that performsimage formation with a non-decoloring ink forms an identificationinformation image corresponding to identification information on a sheetwhen image formation is performed in the rewritable print mode. In anormal image forming process other than the rewritable print mode, imageformation is performed by a normal ink jet method using a non-decoloringink.

Moreover, image formation in the reproduction mode is performedsimilarly to the case of the first embodiment. For example, the imagereading sensor 24′ reads an identification information image on a sheetsupplied from the image formed sheet supply unit 28, and the secondimage forming unit 10 forms an image with a decoloring ink based on theimage data corresponding to identified identification information.

The functional blocks of the MFP 1 a of the present embodiment are thesame as the functional blocks of the MFP 1 of the first embodiment shownin FIG. 3. Moreover, the details of the image forming method in therewritable print mode and the image forming method in the reproductionmode by the MFP 1 a of the present embodiment are the same as those ofthe processes shown in FIGS. 6 and 7 and described in the firstembodiment, and description thereof will be omitted.

In the MFP 1 a having such a configuration, similarly to the firstembodiment, it is possible to form an identification information imagethat identifies a sheet with a non-decolorable colorant (non-decoloringink) during image formation in the rewritable print mode. Moreover, itis possible to store the image data based on which an image is formedwith a decolorable colorant (decoloring ink) and the sheetidentification information to be correlated to each other. Therefore, itis possible to reproduce an image even when the image formed with adecolorable colorant is decolored and disappears.

Moreover, since the MFP 1 a of the present embodiment has the first andsecond image forming units 80 and 10 which both use an ink jet method,it is possible to downsize the MFP 1 a further than the MFP 1 of thefirst embodiment.

Although the present embodiment was described such that the print heads80K to 80Y of the first image forming unit 80 are configured to form anink image on the intermediate transfer belt and transfer the image to asheet, the invention is not limited to such a configuration, but aconfiguration of a normal ink jet method may be used in which the printheads 80K to 80Y discharge ink directly to a sheet to form an image.

As a modification of the MFP 1 a of the second embodiment, an MFP 1 a'shown in FIG. 11 is possible. FIG. 11 is a diagram showing theconfiguration of the MFP 1 a′ which is a modification of the MFP 1 a ofthe second embodiment. The MFP 1 a′ has a configuration in which printheads 80K to 80Y discharging a non-decoloring ink which is anon-decolorable colorant and print heads 80K′ to 80Y′ discharging adecoloring ink which is a decolorable colorant are arranged at the samelocation, and image formation is performed by the print heads. In therewritable print mode, an identification information image thatidentifies a sheet is formed with a non-decoloring ink discharged fromthe print heads 80K to 80Y, and an image is formed based on image dataacquired as a print job with a decoloring ink discharged from the printheads 80K′ to 80Y′. Moreover, in the reproduction mode, a sensor such asthe image reading sensor 24′ reads the identification information imageformed on a sheet, on which a colorant of an image is decolored, andimage data corresponding to identified identification information areformed on a sheet with a decoloring ink discharged from the print heads80K′ to 80Y′. The image may be reproduced with a non-decolorablecolorant.

Third Embodiment

Next, a third embodiment will be described. An MFP 1 b of the presentembodiment is configured to perform both image formation with anon-decolorable colorant and image formation with a decolorable colorantby an electrophotographic method. In the following, the MFP 1 b of thepresent embodiment will be described, and the same configuration as theabove-described embodiments will be denoted by the same referencenumerals and description thereof will be omitted.

FIG. 12 is a diagram showing the configuration of the MFP 1 b accordingto the present embodiment. The MFP 1 b of the present embodimentincludes an image forming unit 8′ that is made up of the photoconductivedrums 8K to 8Y that use a non-decolorable colorant and constitute thefirst image forming unit 8 of the first embodiment and photoconductivedrums 8K′, 8C′, 8M′, and 8Y′ that are disposed to be adjacent to each ofthe photosensitive drums 8K to 8Y so as to form a developer image with adecolorable colorant. The photoconductive drums 8K′, 8C′, 8M′, and 8Y′of the image forming unit 8′ are configured to form a developer imagewith decolorable colorants of the colors black, cyan, magenta, andyellow, respectively.

Therefore, in the MFP 1 b of the present embodiment, when imageformation is performed in the rewritable print mode, image data acquiredas an image forming job are formed with a developer image formed by thephotoconductive drums 8K′ to 8Y′ that use a decolorable colorant, and anidentification information image is formed with a developer image formedby the photoconductive drums 8K to 8Y that use a non-decolorablecolorant. That is to say, a developer image is formed on thephotoconductive drums 8K′ to 8Y′ with a decolorable colorant based onthe image data acquired as the print job, and a developer image isformed on the photoconductive drums 8K to 8Y with a non-decolorablecolorant based on the identification information image. The developerimage formed with the non-decolorable colorant and the developer imageformed with the decolorable colorant are transferred (primarilytransferred) from the respective photoconductive drums 8K to 8Y and 8K′to 8Y′ to the intermediate transfer belt 8B. In this way, an image thatis formed with the decolorable colorant and acquired as a print job andthe developer image that is made up of the identification informationimage formed with the non-decolorable colorant are formed on theintermediate transfer belt 8B. The developer image is transferred(so-called secondarily transferred) to a sheet at a transfer position T,and the developer image on the sheet is thermally fixed to the sheet bythe fixing device 8F. As described above, the MFP 1 b of the presentembodiment is able to form the image formed with the decolorablecolorant and the identification information image formed with thenon-decolorable colorant at the same time through one process involvingtransferring and heat-fixing of a developer image to the sheet.

Moreover, in the MFP 1 b of the present embodiment, when image formationis performed in the reproduction mode, for example, similarly to thecase of the first embodiment, the image reading sensor 24′ reads anidentification information image on a sheet supplied from the imageformed sheet supply unit 28, and image formation is performed with adecoloring ink based on image data corresponding to identificationinformation that is identified from the read identification informationimage.

The functional blocks of the MFP 1 b of the present embodiment are thesame as the functional blocks of the MFP 1 of the first embodiment shownin FIG. 3. However, the first image forming unit control unit 112controls the photoconductive drums 8K to 8Y corresponding to the firstimage forming unit to perform image formation with a non-decolorablecolorant, and the second image forming unit control unit 114 controlsthe photoconductive drums 8K′ to 8Y′ corresponding to the second imageforming unit 10 to perform image formation with a decolorable colorant.Moreover, other function such as the intermediate transfer belt 8B andthe fixing device 8F may be controlled either by the first image formingunit control unit 112 or the second image forming unit control unit 114.

Moreover, the details of the image forming method in the rewritableprint mode and the reproduction mode according to the present embodimentare the same as those of the processes shown in FIGS. 6 and 7 anddescribed in the first embodiment, and description thereof will beomitted.

According to the above-described MFP 1 b of the present embodiment,similarly to the first and second embodiments, it is possible to form anidentification information image that identifies a sheet with anon-decolorable colorant (non-decoloring ink) during image formation inthe rewritable print mode. Moreover, it is possible to store the imagedata formed with a decolorable colorant (decoloring ink) and the sheetidentification information to be correlated to each other. Therefore, itis possible to reproduce an image even when the image formed with adecolorable colorant is decolored and disappears.

Fourth Embodiment

Next, a fourth embodiment will be described. An MFP 1 c according to thepresent embodiment causes the image reading unit 12 to read anidentification information image on a sheet, on which an image isdecolored, during image formation in the reproduction mode. Thus, theMFP 1 c is able to reproduce the image on a sheet different from theoriginal sheet, from which the identification information image wasread, by acquiring image data corresponding to identificationinformation that is identified from the identification information imageand forming an image based on the acquired image data on the sheet.Therefore, the MFP 1 c has the same configuration as the MFP shown inFIG. 1. Thus, the image formation in the reproduction mode according tothe present embodiment, namely the process wherein the image readingunit 12 reads the identification information image, and an image thatwas decolored is reproduced by forming the image on a sheet differentfrom the original sheet from which the identification information imagewas read can be applied to any of the MFPs shown in FIGS. 2, 9, 10, 11,and 12.

Next, the functional blocks for realizing the process in thereproduction mode by the MFP 1 c of the present embodiment will bedescribed. FIG. 13 is a functional block diagram showing the function inthe reproduction mode of the MFP 1 c according to the presentembodiment.

As functional blocks different from the functional blocks shown in FIG.5, the MFP 1 c includes an image reading control unit 120, an image datastorage control unit 116, and a first image forming unit control unit112. The other functional blocks such as the image reproduction jobacquiring unit 502, the sheet supply control unit 108, the image dataacquiring unit 504, and the second image forming unit control unit 114are the same as those of the first embodiment. However, when an image tobe reproduced is formed by the first image forming unit 8 rather than bythe second image forming unit 10, the first image forming unit controlunit 10 may control the first image forming unit 8 to perform imageformation.

When the image reproduction job acquiring unit 502 acquires an imagereproduction job instructing to execute image formation in thereproduction mode through an operation input on the operation input unit16 or the like, the image reading control unit 120 causes the imagereading unit 12 to scan a sheet on which an image was decolored, andwhich is placed on a document table or the like of the image readingunit 12 and read an identification information image formed on the sheetwith a non-decolorable colorant. Then, based on the identificationinformation identified from the identification information image, theimage data acquiring unit 504 references the image data DB 100 of theHDD 6 to acquire corresponding image data. In this way, it is possibleto reproduce the decolored image by forming an image based on the imagedata on a sheet transported to the image forming unit. At that time, asdescribed above, in the present embodiment, image formation is performedon a sheet different from the sheet on which the decolored image wasformed. Specifically, the sheet supply control unit 108 may control thesheet supply unit 18 to transport a reused sheet from the reused sheetsupply unit 18 b so that the image forming unit performs image formationon the reused sheet. Alternatively, the sheet supply control unit 108may control the sheet supply unit 18 to transport an unused sheet fromthe sheet supply unit 18 a storing unused sheets so that image formationis performed on the unused sheet.

The image data storage control unit 116 is the same function as thefirst embodiment. In the present embodiment, when the second imageforming unit 10 forms an image to be reproduced as an image formed witha decolorable colorant (alternatively, when the photoconductive drums8K′ to 8Y′ using a decolorable colorant shown in FIG. 12 form adeveloper image of an image to be reproduced), the image data storagecontrol unit 116 executes a process of registering the image data formedon the sheet and the sheet identification information to the image database of the HDD 6 in a correlated manner. By doing so, even when animage disappears again due to decoloring, it is possible to reproducethe image from the different sheet, on which the image is reproduced, byany of the above-described reproducing methods.

Moreover, if an image reproduction job contains an instruction to forman image to be reproduced on an unused sheet, when the imagereproduction job acquiring unit 502 acquires the image reproduction job,the first image forming unit control unit 112 generates newidentification information assigned to the sheet and causes the firstimage forming unit 8 to form an identification information imagecorresponding to the identification information with a non-decolorablecolorant. When new identification information is generated, the imagedata storage control unit 116 stores the identification information andthe reproduced image data in the image data DB 100 in a correlatedmanner. In FIG. 13, the flow of signals when the image reproduction jobcontains an instruction to form an image to be reproduced on an unusedsheet is denoted by the dotted line.

Next, the flow of processing in the MFP 1 c of the present embodimentwhen image formation is performed in the reproduction mode will bedescribed. FIG. 14 is a flowchart showing the flow of an image formingprocess in the reproduction mode by the MFP 1 c.

First, in Act 301, a user places a sheet on which a decolored image isformed on the image reading unit 12 and operates the operation inputunit 16 to issue an instruction to execute an image forming process inthe reproduction mode. In Act 301, the image reproduction job acquiringunit 502 acquires an image reproduction job.

Subsequently, in Act 302, the image reading control unit 120 causes theimage reading unit 12 to execute a process of reading an identificationinformation image formed in a predetermined region of a sheet placed onthe image reading unit 12.

Subsequently, in Act 303, the image data acquiring unit 504 referencesthe image data DB 100 based on identification information that isidentified from the identification information image read by the imagereading unit 12 to acquire image data whose registration time is thelatest among the image data correlated to the identificationinformation.

Subsequently, in Act 304, the second image forming unit control unit 114executes a process of causing the second image forming unit 10 to formthe image data acquired in Act 303 on a sheet.

Subsequently, in Act 305, the image data storage control unit 116executes a process of registering the image data formed for reproductionon the sheet by the second image forming unit 10 and the identificationinformation assigned to the sheet, on which an image is formed based onthe image data, to the image data DB 100 in a correlated manner.

In Act 304, when the sheet to be printed is a reused sheet, the imagereading sensor 24 shown in FIG. 2 or the like, or if the MFP includesthe image formed sheet supply unit 28 and the image reading sensor 24′as shown in FIG. 9 or the like, the image reading sensor 24′ reads theidentification information image that is formed on the reused sheettransported for forming, and the identification information is stored inthe image data DB 100 to be correlated to the image data based on whichthe image is formed in Act 304.

On the other hand, when the sheet on which an image to be reproducedwill be formed is an unused sheet supplied from the sheet supply unit 18a, as described above, the first image forming unit control unit 112generates new identification information that is not registered byreferencing the image data DB 100 and causes the first image formingunit 8 to form an identification information image corresponding to theidentification information. Moreover, the image data storage controlunit 116 stores the reproduced image data and the newly assignedidentification information in the image data DB 100 in a correlatedmanner.

The image forming process in the reproduction mode by the MFP 1 caccording to the present embodiment was described hereinabove.

According to the present embodiment, it is possible to form an image tobe reproduced on a sheet different from an original sheet having adecolored image. Moreover, since an identification information image isread by the image reading unit 12 that is provided to a general MFP, itis possible to reproduce an image on a sheet without a dedicated imagereading sensor such as the image reading sensor 24.

Fifth Embodiment

Next, a fifth embodiment will be described. Although the MFPs of theabove-described embodiments are configured to store the image data DB100 in the HDD 6, an MFP 1 d of the present embodiment is configureddifferently in that the image data DB 100 is stored in an externalserver 500 connected via the network 150.

FIG. 15 is a diagram showing the configuration of the MFP 1 d accordingto the present embodiment and a system including the server 500 in whichthe image data DB 100 is stored.

The MFP 1 d may have the same configuration as the MFP of the otherembodiments described above, except that the image data DB 100 is notstored in the HDD 6. Moreover, the functional blocks of the MFP 1 d arethe same as the functional blocks shown in FIGS. 3 and 5, anddescription thereof will be omitted.

The server 500 stores the image data DB 100 in which image data base onwhich the image is formed by the MFP 1 d and identification informationfor identifying an image formed sheet are stored in a correlated manner.

In a system including the MFP 1 d and the server 500 having such aconfiguration, when the MFP 1 d performs image formation in therewritable print mode, the MFP 1 d accesses the server 500 via thenetwork 150 and stores a formed image and identification information inthe image data DB 100 stored in the server 500 in a correlated manner.Moreover, even when new identification information is generated, thefirst image forming unit control unit 112 of the MFP 1 d accesses theimage data DB 100 of the server 500 and generates identificationinformation that is not been registered. Moreover, when image formationis performed in the reproduction mode, the MFP 1 d reads anidentification information image on a sheet on which an image to bereproduced is formed, acquires corresponding image data from the imagedata DB 100 of the server 500 based on identification informationidentified from the identification information image, and reproduces theimage on a sheet. As described above, even when the image data DB 100 isstored outside the MFP, similarly to the above-described embodiments, itis possible to perform the image forming process in the rewritable printmode and the reproduction mode. The details of the image forming processin the rewritable print mode and the reproduction mode are the same asthose of the above-described embodiments, and description thereof willbe omitted.

Sixth Embodiment

Next, a sixth embodiment will be described. FIG. 16 is an enlarged viewof the vicinity of the sheet supply unit 18 of an MFP 1 e according tothe present embodiment.

Like the MFP 1′ shown in FIG. 9 and described as the modification of thefirst embodiment, the MFP 1 e of the present embodiment includes thefollowing units at positions adjacent to the reused sheet supply unit 18b (first sheet storage unit): the image formed sheet supply unit 28, theimage reading sensor 24′ that reads an identification information imageformed on a sheet, the decoloring device 26 that is disposed downstreamof the image reading sensor 24′ and upstream of the reused sheet supplyunit 18 b and the like. The MFP 1 e further includes a disused sheetstorage unit 130 (second sheet storage unit) that is disposed downstreamof a transport path different from a transport path to the reused sheetsupply unit 18 b so as to store sheets that are not reused. Thus, theMFP 1 e of the present embodiment includes a transport path switchingunit 140 serving as a sheet sorting unit that selectively supplies asheet transported from the image formed sheet supply unit 28 to thetransport path to the reused sheet supply unit 18 b being connected tothe decoloring device 26 or to the transport path to the disused sheetstorage unit 130 based on whether an identification information image isread by the image reading sensor 24′.

The transport path switching unit 140 is formed, for example, by a pairof plates facing in the vertical direction and is switched between aposition wherein a sheet is transported towards the reused sheet supplyunit 18 b and a position wherein a sheet is transported towards thedisused sheet storage unit 130. In this way, sheets are transported toeither the reused sheet supply unit 18 b or the disused sheet storageunit 130. The transport path switching unit 140 is not limited to thepair of illustrated plates, but may have any configuration as long as itis capable of selectively switching a transport destination to either ofthe reused sheet supply unit 18 b and the disused sheet storage unit130. For example, a flap-like transport path switching unit 140 is alsopossible.

According to the described configuration, when a sheet stored in theimage formed sheet supply unit 28 is transported, the image readingsensor 24′ disposed upstream of the transport path switching unit 140reads an identification information image on the sheet. If theidentification information image was read properly as a result of thereading, it can be determined that an image is formed on the sheet witha decolorable colorant, and it is therefore possible to decolor an imageon the sheet by a decoloring process and obtain a sheet like a blankpaper. Therefore, in this case, the transport path switching unit 140performs switching so that the sheet is transported to the reused sheetsupply unit 18 b via the decoloring device 26. Thereafter, thedecoloring device 26 decolors the sheet by a decoloring process such asheating, and the decolored sheet is stored in the reused sheet supplyunit 18 b in a reusable state like a blank paper. The sheets stored inthe reused sheet supply unit 18 b are reused for forming in therewritable print mode and the reproduction mode.

On the other hand, when the identification information image was notread by the image reading sensor 24′, it can be determined that an imageis not formed on the sheet with a decolorable colorant and cannot bedecolored. Thus, the transport path switching unit 140 performsswitching so that the sheet is transported to the disused sheet storageunit 130.

Therefore, according to the MFP 1 e of the present embodiment, it ispossible to read an identification information image formed on a sheetwith a non-decolorable colorant, perform a decoloring process on areusable sheet to obtain a sheet like a blank sheet that can be reused,and store the decolored sheet in the reused sheet supply unit 18 b.Moreover, it is possible to transport a sheet that can be neitherdecolored nor reused to the disused sheet storage unit 130. Therefore,it is possible to sort sheets into reusable sheets and non-reusablesheets and use only the reusable sheets for image formation withoutrequiring a user's determination with the naked eye as to whether or notan image formed on a sheet is formed with a decolorable colorant.Moreover, even when the user tries to discriminate between the sheets,it is difficult to differentiate an image formed with a decolorablecolorant from an image formed with a non-decolorable colorant andreliably sort the sheets into reusable sheets and sheets to be disused.

Next, functional blocks for realizing the sorting process by theabove-described transport path switching unit 140 of the presentembodiment will be described. FIG. 17 is a functional block diagram ofthe MFP 1 e according to the present embodiment.

The MFP 1 e includes a sorting instruction acquiring unit 200, the imagereading sensor control unit 110, a transport path switching control unit202 serving as a sorting control unit, and a decoloring control unit204.

The sorting instruction acquiring unit 200 acquires a sortinginstruction when a user places sheets that the user wants to reuse bydecoloring images formed on the sheets on the image formed sheet supplyunit 28 and issues an instruction through an operation input on theoperation input unit 16 to execute a process of performing a decoloringprocess on the placed sheets and sorting the sheets into sheets to bereused and sheets to be disused.

When the sorting instruction acquiring unit 200 acquires the sortinginstruction, the image reading sensor control unit 110 executes aprocess of causing the image reading sensor 24′ to read anidentification information image formed on a sheet that is transportedfrom the image formed sheet supply unit 28 by transport rollers or thelike.

The transport path switching control unit 202 determines whether or notthe image reading sensor 24′ acquired the identification informationimage under the control of the image reading sensor control unit 110.Then, the transport path switching control unit 202 changes theswitching direction of the transport path switching unit 140 based onthe determination results so that sheets subjected to the readingprocess are transported to the reused sheet supply unit 18 b or thedisused sheet storage unit 130.

The decoloring control unit 204 controls the decoloring device 26 toexecute a decoloring process on a transported sheet when it isdetermined that an image is formed on the sheet with a decolorablecolorant and a decoloring process can be performed based on thedetermination results by the transport path switching control unit 202as to whether or not the image reading sensor 24′ was able to read theidentification information image, and when the sheet is transported tothe reused sheet supply unit 18 b.

The functional blocks for realizing the sheet sorting process using theidentification information image and the decoloring process by the MFP 1e according to the present embodiment was described hereinabove.

Next, the flow of the sheet sorting process by the MFP 1 e of thepresent embodiment will be described. FIG. 18 is a flowchart showing theflow of the sheet sorting process by the MFP 1 e.

First, in Act 401, the sorting instruction acquiring unit 200 acquiresan instruction from the operation input unit 16 to execute a process ofsorting image formed sheets stored in the image formed sheet supply unit28.

Subsequently, in Act 402, when the sorting instruction acquiring unit200 acquired the sorting instruction, the image reading sensor controlunit 110 causes the image reading sensor 24′ to execute a process ofreading an identification information image among images that are formedon a sheet transported from the image formed sheet supply unit 28. InAct 403, the transport path switching unit 202 determines whether or notthe identification information image was read by the image readingsensor 24′.

When it was determined that the identification information image wasread (Act 403: Yes), the transport path switching control unit 202determines that images are formed on the sheet with a decolorablecolorant and executes a process of changing the switching direction ofthe transport path switching unit 140 so that the sheet is transportedto the reused sheet supply unit 18 b.

Subsequently, in Act 405, the decoloring control unit 204 controls thedecoloring device 26 to execute a process of decoloring images formed onthe sheet transported towards the reused sheet supply unit 18 b.

Subsequently, in Act 406, transport rollers or the like, which are notshown, transport the sheet on which images are decolored and whichbecame a blank paper to the reused sheet supply unit 18 b.

On the other hand, when it was determined that the identificationinformation image was not read by the image reading sensor 24′ (Act 403:No), the transport path switching control unit 202 determines in Act 403that images are formed on the sheet with a non-decolorable colorant andexecutes in Act 407 a process of changing the switching direction of thetransport path switching unit 140 so that the sheet is transported tothe disused sheet storage unit 130.

Subsequently, in Act 408, transport rollers or the like, which are notshown, transport the sheet to be stored in the disused sheet storageunit 130.

The flow of the sheet sorting process by the MFP 1 e of the presentembodiment was described hereinabove.

As described above, according to the MFP 1 e of the present embodiment,it is possible to sort the sheets simply into sheets to be reused andsheets to be disused by using the identification information imageformed during the image forming process in the rewritable print mode.

Although the present embodiment was described such that a sheet isselectively reused or disused based on whether or not the identificationinformation image was read, the invention is not limited to this. If theidentification information image was read, the sheet may be selectivelyreused or disused based on a determination as to whether or notcorresponding identification information is registered in the image dataDB 100, and if registered, the identification information is stored tobe correlated to image data. In this case, for example, an accuratesorting process is possible since it is even possible to sort, as asheet to be disused, a sheet on which an image is formed with anidentification information image but cannot be decolored because imagesare formed with a non-decolorable colorant.

Moreover, although the present embodiment was described such that thedetermination as to whether a sheet will be reused or disused is madebased on whether or not the identification information image formed onthe sheet was read, the invention is not limited to this. A simple imagesuch as a mark or a character string capable of displaying the fact thatan image formed on a sheet is formed with a decolorable colorant may beformed on a sheet with a non-decolorable colorant. For example, whenimage formation is performed in the rewritable print mode, apredetermined symbol displaying the fact that images are formed with adecolorable colorant may be formed at a predetermined position outsidethe region in which an image based on a print job is formed. In thesorting process described in the present embodiment, the predeterminedposition is read by the image reading sensor 24′ or the like. In thiscase, when the predetermined symbol is read, it is determined thatimages are formed on the sheet with a decolorable colorant, and thesorting process is performed so that the sheet is transported to thereused sheet supply unit 18 b.

Seventh Embodiment

Next, a seventh embodiment will be described. FIG. 19 is a diagramshowing the configuration of an MFP 1 g according to the presentembodiment. The MFP 1 g of the present embodiment is different from theMFP 1 of the first embodiment, in that the MFP 1 g includes a fixing anddecoloring device 8F′ that has a function of decoloring images formedwith a decolorable colorant in addition to a fixing function instead ofthe fixing device 8F described in the first embodiment. The MFP 1 g ofthe present embodiment has a configuration that solves problems thatarise if a fixing device also serves as a decoloring device. The otherconfigurations are the same as those of the MFP 1 of the firstembodiment, and description thereof will be omitted. That is, the MFP 1g has a configuration in which the first image forming unit 8 performsimage formation with a non-decolorable colorant by anelectrophotographic method, and the second image forming unit 10performs image formation with a decolorable colorant by an ink jetmethod. The configuration of the MFP 1 g according to the presentembodiment will be described below.

First, the problems that arise when the fixing device also serves as thedecoloring device will be described.

A first problem is that if the decoloring temperature of a decolorablecolorant is lower than the fixing temperature, when a sheet subjected toa fixing process at a temperature higher than the decoloring temperatureis introduced into the second image forming unit 10 in thehigh-temperature state higher than the decoloring temperature, thedecoloring ink which is the decolorable colorant of the second imageforming unit 10 will be decolored by the heat of the sheet (see FIG.20).

A second problem is that if the fixing temperature is lower than thedecoloring temperature, when a decoloring process is performed on asheet at a temperature higher than the fixing temperature, and asubsequent sheet is subsequently subjected to forming with anon-decolorable colorant and a fixing process, so that the fixing anddecoloring device maintains a temperature higher than the fixingtemperature (see FIG. 21), a high-temperature offset will occur duringheat-fixing of a developer image, thus leading to defective forming.

To solve the first problem, as shown in FIG. 22, it is necessary to cooldown the temperature of a sheet subjected to a fixing process by thefixing and decoloring device 8F′ to a temperature (e.g., 90 to 110° C.)lower than the decoloring temperature (e.g., 130° C. or higher) and passthe sheet through the second image forming unit. If a sheet subjected toa decoloring process by the fixing and decoloring device 8F′ wasdecolored at a temperature higher than the decoloring temperature, thesheet may be cooled down similarly because the temperature of the sheetwill be higher than the decoloring temperature.

On the other hand, to solve the second problem, it is necessary toperform a decoloring process at a temperature higher than the fixingtemperature, cool down the fixing and decoloring device 8F′, and thenperform image formation of a subsequent sheet.

As a means for solving the problems described above, first, in order tosolve the first problem, the MFP 1 g of the present embodiment mayinclude a sheet cooling device 300 that is disposed between the fixingand decoloring device 8F′ and the second image forming unit 10 so as tocool down a sheet subjected to a fixing process. As the sheet coolingdevice 300, for example, an air blowing device such as a fan that blowsa cooling air to a sheet being transported or a cooling plate that comesinto contact with a sheet to perform cooling may be used. Moreover, atransport path for cooling may be provided instead of the sheet coolingdevice 300. That is, it is possible to design a transport distancebetween the fixing and decoloring device 8F′ and the second imageforming unit 10 to be longer so that a sheet can be cooled down duringtransport.

Moreover, in order to solve the second problem, a fixing and decoloringdevice cooling device 302 that cools down the fixing and decoloringdevice 8F′ may be provided. As the fixing and decoloring device coolingdevice 302, an air blowing device such as a fan that blows a cooling airto the fixing and decoloring device 8F′ may be used, and a Peltierdevice may be provided to the fixing and decoloring device 8F′ toperform temperature control.

The MFP 1 g of the present embodiment is an MFP that includes two imageforming units: a first image forming unit that performs image formationwith a non-decolorable colorant by an electrophotographic method; and asecond image forming unit that performs image formation with adecolorable colorant by an ink jet method. According to the MFP 1 g, forexample, even when a sheet formed with a non-decolorable colorant by anelectrophotographic method is heated by a fixing process to atemperature higher than the decoloring temperature of a decolorablecolorant used in the second image forming unit, since the sheet passesthrough the second image forming unit after the sheet is cooled down toa temperature lower than the decoloring temperature, the decolorablecolorant will not be decolored.

Moreover, even if the decoloring temperature is higher than the fixingtemperature, when a decoloring process is performed on a sheet by thefixing and decoloring device, and a fixing process is subsequentlyperformed to another subsequent sheet by an electrophotographic method,images formed by the electrophotographic method will not have defectsresulting from a high-temperature offset or the like since the fixingand decoloring device 8F′ is cooled.

In addition, a program that causes a computer constituting an imageforming apparatus to execute the above-described operations can beprovided as an image forming program. Although the present embodimentwas illustrated such that the program for realizing the functionsimplementing the invention is recorded in advance in a storage regionprovided in the apparatus, the invention is not limited to this. Asimilar program may be downloaded to the apparatus from a network, or asimilar program stored in a computer-readable recording medium can beinstalled in the apparatus. The recording medium may be in any form thatcan store a program and can be read by a computer. Specifically, suchrecording media may include, for example, internal storage devicesarranged within a computer such as ROM and RAM, portable storage mediasuch as CD-ROM, flexible disk, DVD disk, magneto-optical disk and ICcard, database which holds computer programs, another computer and itsdatabase, and a transmission medium on a network line. The functionsthat can be acquired in advance by installation and downloading may berealized in cooperation with the OS (operating system) in the apparatus.

A part or an entirety of the program may be an execution module that isdynamically generated.

The invention can be embodied in a variety of other forms withoutdeparting from the spirit or major features thereof. Therefore, theembodiments described above are exemplary only in all respects, and arenot intended to limit the scope of the invention. The scope of theinvention should be defined by the accompanying claims and should not berestricted to the main body of the specification. Furthermore, allchanges, various improvements, substitutions and alterations made withinthe equivalent range of the claims would fall within the scope of theinvention.

As described in detail above, according to the invention, it is possibleto provide an image forming apparatus capable of reliably reproducing adecolored image even when an image formed with a decolorable colorant iscarelessly decolored and disappears.

1. An image forming apparatus comprising: an image data acquiring unitthat acquires image data of an image formed on a sheet; anidentification information acquiring unit that acquires identificationinformation that identifies the sheet on which the image is formed; animage forming unit that forms an image based on the image data acquiredby the image data acquiring unit on the sheet with a decolorablecolorant which becomes colorless by a predetermined chemical reactionand that forms an identification information image based on theidentification information on the sheet with a non-decolorable colorantwhich does not become colorless by the chemical reaction by which thedecolorable colorant becomes colorless; and a storage control unit thatstores the identification information and the image data of the image tobe formed on the sheet, on which the identification information imagecorresponding to the identification information is formed, in apredetermined storage region in a correlated manner.
 2. The apparatusaccording to claim 1, wherein the image forming unit includes: a firstimage forming unit that forms the identification information image onthe sheet with the non-decolorable colorant; and a second image formingunit that forms the image on the sheet with the decolorable colorant. 3.The apparatus according to claim 2, wherein one of the first and secondimage forming units is an image forming unit of an ink jet method, andthe other image forming unit is an image forming unit of anelectrophotographic method, and images are formed by an ink jet methodafter images are formed by an electrophotographic method.
 4. Theapparatus according to claim 1, further comprising an identificationinformation image reading unit that reads the identification informationimage formed on the sheet, wherein the image forming unit forms an imageon a sheet, from which the identification information image is read bythe identification information image reading unit, with the decolorablecolorant based on the image data acquired by the image data acquiringunit, and the storage control unit stores the identification informationcorresponding to the identification information image read by theidentification information image reading unit and image data of an imageformed on the sheet, from which the identification information image isread, in a correlated manner.
 5. The apparatus according to claim 1,further comprising: an identification information image reading unitthat reads an identification information image formed on the sheet; anda stored image data acquiring unit that acquires image data that isstored to be correlated to the identification information correspondingto the identification information image read by the identificationinformation image reading unit from the predetermined storage region. 6.The apparatus according to claim 5, wherein the image forming unit formsan image on a sheet based on the image data acquired by the stored imagedata acquiring unit.
 7. The apparatus according to claim 6, wherein theimage forming unit forms the image on the sheet from which anidentification information image is read by the identificationinformation image reading unit.
 8. The apparatus according to claim 1,further comprising: an identification information image reading unitthat reads an identification information image formed on the sheet; asheet sorting control unit that performs control so that sheets aretransported to a first sheet storage unit if the identificationinformation image is read by the identification information imagereading unit, and sheets are transported to a second sheet storage unitif the identification information image is not read; and a sheet sortingunit that sorts sheets based on the control of the sheet sorting controlunit.
 9. The apparatus according to claim 3, wherein the first imageforming unit is an image forming unit of an electrophotographic method;wherein the second image forming unit is an image forming unit of an inkjet method, and wherein the apparatus further comprises: a fixing anddecoloring unit that performs a fixing process of thermally fixing adeveloper image formed by the first image forming unit to a sheet andperforms a decoloring process of decoloring images formed with thedecolorable colorant by thermal energy; and a cooling unit that coolsdown a sheet subjected to the fixing or decoloring process by the fixingand decoloring unit to a temperature lower than a decoloring temperatureat which the decolorable colorant is decolored.
 10. The apparatusaccording to claim 3, wherein the first image forming unit is an imageforming unit of an electrophotographic method; wherein the second imageforming unit is an image forming unit of an ink jet method, and whereinthe apparatus further comprises: a fixing and decoloring unit thatperforms a fixing process of thermally fixing a developer image formedby the first image forming unit to a sheet and performs a decoloringprocess of decoloring images formed with the decolorable colorant bythermal energy; and a cooling unit that cools down the fixing anddecoloring unit if images formed on a sheet were decolored by the fixingand decoloring unit.
 11. An image forming method comprising: acquiringimage data of an image formed on a sheet; acquiring identificationinformation that identifies the sheet on which the image is formed;forming an image based on the acquired image data on the sheet with adecolorable colorant which becomes colorless by a predetermined chemicalreaction and forming an identification information image based on theidentification information on the sheet with a non-decolorable colorantwhich does not become colorless by the chemical reaction by which thedecolorable colorant becomes colorless; and storing the identificationinformation and the image data of the image to be formed on the sheet,on which the identification information image corresponding to theidentification information is formed, in a predetermined storage regionin a correlated manner.
 12. The method according to claim 11, furthercomprising: reading the identification information image formed on thesheet; forming an image on the sheet, from which the identificationinformation image is read, with the decolorable colorant based on theacquired image data; and storing the identification informationcorresponding to the read identification information image and imagedata of an image to be formed on the sheet, from which theidentification information image is read, in a correlated manner. 13.The method according to claim 11, further comprising: reading theidentification information image formed on the sheet; and acquiringimage data that are stored to be correlated to the identificationinformation corresponding to the read identification information imagefrom the predetermined storage region.
 14. The method according to claim13, wherein an image is formed on a sheet based on the image dataacquired from the predetermined storage region.
 15. The method accordingto claim 14, wherein the image is formed on the sheet from which theidentification information image is read.
 16. The method according toclaim 11, further comprising: reading the identification informationimage formed on the sheet; and transporting sheets to a first sheetstorage unit if the identification information image is read andtransporting sheets to a second sheet storage unit if the identificationinformation image is not read, thus sorting the sheets.
 17. Acomputer-readable recording medium having an image forming programrecorded therein, the program causing a computer to execute processingcomprising: acquiring image data of an image formed on a sheet;acquiring identification information that identifies the sheet on whichthe image is formed; forming an image based on the acquired image dataon the sheet with a decolorable colorant which becomes colorless by apredetermined chemical reaction and forming an identificationinformation image based on the identification information on the sheetwith a non-decolorable colorant which does not become colorless by thechemical reaction by which the decolorable colorant becomes colorless;and storing the identification information and the image data of theimage to be formed on the sheet, on which the identification informationimage corresponding to the identification information is formed, in apredetermined storage region in a correlated manner.
 18. The recordingmedium according to claim 17, wherein the processing further comprises:reading the identification information image formed on the sheet;forming an image on the sheet, from which the identification informationimage is read, with the decolorable colorant based on the acquired imagedata; and storing the identification information corresponding to theread identification information image and image data of an image to beformed on the sheet, from which the identification information image isread, in a correlated manner.
 19. The recording medium according toclaim 17, wherein the processing further comprises: reading theidentification information image formed on the sheet; and acquiringimage data that are stored to be correlated to the identificationinformation corresponding to the read identification information imagefrom the predetermined storage region.
 20. The recording mediumaccording to claim 17, wherein the processing further comprises: readingthe identification information image formed on the sheet; and performingcontrol so that sheets are transported to a first sheet storage unit ifthe identification information image is read and that sheets aretransported to a second sheet storage unit if the identificationinformation image is not read, thus sorting the sheets.